The present invention relates to arc deposition apparatus. More specifically, this invention relates to improved filtered cathodic vacuum arc apparatus and methods of use thereof utilising multiple available targets.
A number of plasma-based deposition methods have in recent years replaced sputtering systems as the desirable means of depositing thin coatings on a wide range of substrates.
Arc deposition processes generally include applying an electric field between a cathode target and an anode, both of which are located within an evacuated chamber. Free electrons flow from the cathode to the anode, creating a plasma vapour of positively charged target ions and negatively charged electrons in the chamber, the ions moving along a line of sight away from the target. A substrate to be coated is placed within the chamber in the line of sight of the target and therefore is coated by the ions.
Arc deposition apparatus, such as Filtered cathodic vacuum arc (FCVA) deposition apparatus, employ low pressures within the chamber during operation. The targets of these devices typically last about 10,000 operational seconds. Once a target has been depleted the chamber has to be opened in order that the targets can be replaced. Due to the low pressures used within the chamber, it can take more than one day to reestablish the required vacuum.
Present FCVA devices commonly employ the use of a graphite target to provide a tetrahedral amorphous carbon (ta-C) coating on a given substrate. In use, emission of ions from the target can be localized, resulting in an uneven target emission surface. The target emission surface therefore requires frequent grinding so that the deposition surface is as uniform as possible. Grinding must be performed off-line, resulting in unwanted operational downtime.
It is an object of at least a preferred embodiment of the present invention to overcome or ameliorate at least one of the problems of the prior art, or to provide a useful alternative thereto.